We've already shown you MintyBoost, a battery-powered USB charger built from an Altoids tin;…
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Like the solar-powered charger, this pedal-powered charger is based off the previously mentioned MintyBoost charger (which is simply powered by AA batteries). As opposed to the MintyBoost, which is built to be as easy to assemble as possible, the geek quotient that lies within this Instructable is high. That said, if you've got the chops, time, and cash to pull it off (the motor they used cost a whopping $275), it's a really fun idea.